There has been an ever increasing effort by individuals and industry to increase the mobility of handicapped persons. The manual wheel chair soon gave way to the motorized wheel chair with the accompanying accomodation required in gaining access to various buildings and in particular public buildings. With the desire or need for many of these persons to perform various tasks especially those that require the transfer of the person from one work place or position to another various devices such as the instant invention have been invented.
Various types of aerial lift platforms have been provided but fail to satisfy the needs of transporting, in the simplest most positive manner, a handicapped person. The Canadian patent No. 1,157,395 to Grove et al teaches a mobile aerial lift platform apparatus. This apparatus while similar to applicants requires two boom lifting cylinders, it has an extensible boom cylinder and a platform levelling cylinder. Applicants device has one lifting cylinder and has a non extensible boom surrounding a self levelling platform link for continually supporting the platform in a level position. Applicants device also includes a remotely controllable or manually controllable hydraulic circuit for its operation.
An additional passenger platform patent is revealed in Canadian patent No. 1,220,434. This patent requires a basic boom, a central boom-part and a jib each operated by a piston-cylinder linkage while the platform is held horizontal by a reversible motor through a reduction gear and a control means including an inclinometer. As pointed out above applicants device has a single non extensible boom surrounding a connecting link for a continuous automatic mechanical levelling of the platform as it is lifted, swung and extended to a desired location.
A further passenger platform wheel chair lift is revealed in Canadian patent No. 1,087,555. This patent teaches a wheel chair support structure that slides on a track back and forth and is raised and lowered by winch means. While the platform remains level at all times there is absolutely no possible transverse motion of the platform and support arms nor is there provided any lateral pivoting of the platform at the end of the extended position as taught by applicants device.